CB

Quick summary of what we discussed:

1. convert database columns 1...4, filters and sortings to new database columns at CB upgrade-installation to get them into clean JSON format. No need for 4 columns hardcoded into lists database anymore, thanks to repeat use. Beware that old database storages have multiple escapings done at database level, that are not needed anymore. So converting old format in lists table at CB upgrade is really needed.
2. Not make it look like now for the filter, sorting, and columns LOL (as too hard to make it look same), but directly implement them with repeat usage.
3. sorting can be repeat of select2 of field + drop-down ASC/DESC
4. similar for filtering (actually similar too to what i did for Users-advanced-filter) in simple mode (and as is for advanced mode, except storage needs to be done in a new separate column)
5. for columns, possibly multiselect2 with ordering or 2 nested repeats: Outer for column (at begin can be fixed 4 if much simpler than variable lol) repeats horizontally with name and inner repeats, and inner ones to select fields for each column repeat vertically within each horizontal outer repeat.

Implement basic and advanced modes for sorting as well. This would allow custom SQL sorting to be added as has been requested a lot. It should function same as filter basic/advanced toggle.